Epidermal growth factor receptor-extracellular signal-regulated kinase signaling pathway (EGFR-ERK pathway)

The Epidermal Growth Factor Receptor-Extracellular Signal-Regulated Kinase (EGFR-ERK) signaling pathway is a central molecular cascade that regulates fundamental cellular processes including growth, proliferation, and survival [1, 2]. It is initiated by the binding of ligands such as Epidermal Growth Factor (EGF) to the Epidermal Growth Factor Receptor (EGFR), a transmembrane receptor tyrosine kinase [2, 8]. This binding induces receptor dimerization and autophosphorylation of intracellular tyrosine residues, which serves as a scaffold for adaptor proteins like Grb2 and SOS [3, 11]. These adaptors activate the small GTPase Ras, which then triggers the sequential activation of the Raf-MEK-ERK kinase cascade [3, 9]. Activated ERK translocates to the nucleus where it phosphorylates various transcription factors to modulate gene expression [4, 11]. Dysregulation of this pathway, often through EGFR overexpression or activating mutations in EGFR, Ras, or Raf, is a hallmark of many human cancers, including non-small cell lung cancer and colorectal cancer [5, 12]. Therapeutic interventions targeting this pathway include monoclonal antibodies that block ligand binding and small-molecule inhibitors that target the kinase domains of EGFR or downstream effectors like BRAF and MEK [1, 7]. Clinical challenges include the development of resistance mutations, such as the EGFR T790M mutation, which necessitate the use of next-generation inhibitors [5, 10]. Common side effects of these therapies include dermatologic toxicities and gastrointestinal issues, reflecting the pathway's role in normal epithelial maintenance [13]. Overall, the EGFR-ERK pathway remains a cornerstone of precision oncology and a major focus for drug development [5, 9].

Other names

MAPK/ERK pathwayRas-Raf-MEK-ERK pathwayErbB1 signaling pathwayMitogen-activated protein kinase signaling pathway

The pathway is targeted through several mechanisms: monoclonal antibodies (e.g., cetuximab) bind to the extracellular domain of EGFR to block ligand interaction; small-molecule tyrosine kinase inhibitors (e.g., erlotinib, osimertinib) competitively inhibit ATP binding to the EGFR kinase domain; and downstream inhibitors target BRAF (e.g., vemurafenib) or MEK (e.g., trametinib) to prevent the phosphorylation and activation of the ERK kinase.